Patent Application
20090242182
This invention relates to a plate used in the production of a heat exchanger for exchanging heat between a first fluid and a second fluid.
More specifically, the heat exchanger includes a stack of identical pouches or tubes in which a first fluid circulates, each formed by two plates of sheet metal chased in the form of basins according to this invention. The plates are arranged so that their concavities are facing one another. In addition, the plates are mutually connected in a sealed manner at their peripheries, in particular by brazing.
Such a heat exchanger is commonly used as an evaporator in a refrigerant circuit for the air conditioning of a motor vehicle interior, which refrigerant constitutes the first fluid, and the second fluid is the atmospheric air, or it is used as a heater in a heat-transfer fluid circuit for heating a motor vehicle interior, which heat-transfer fluid constitutes the first fluid, and the second fluid is the atmospheric air.
The atmospheric air passing through the heat exchangers is filled with particles, in particular of water and/or impurities.
At the opening of heat exchangers, particles come into contact with the plate surfaces forming pouches or tubes. In particular, such particles come into contact with the sealed contact areas between two plates.
Such an occurrence contributes to plate corrosion.
This is particularly detrimental at the sealed contact areas between the plates, because it causes a loss of tightness. This results in leakages of the fluid (refrigerant or heat-transfer fluid).
The objective of the invention is therefore to propose a new type of plate for heat exchangers that overcomes the aforementioned disadvantages.
The invention therefore relates to a plate for a flat heat exchanger tube made of chased sheet metal comprising a peripheral edge contained in a plane and forming a connection area. According to this invention, the plate includes at least one wall extending perpendicularly to the plane.
Such a wall enables protection of the junction between two plates forming a heat exchanger tube to be ensured. Indeed, when two plates are assembled to one another, the wall of one of the plates covers the junction area between the plates, and thus insulates said area from external elements, in particular water droplets, metal particles, and so on.
Similarly, such a wall enables the plate to be rigidified by creating a rib that opposes any bending of the latter. It has a very specific advantage in reducing the mass and general dimensions of heat exchangers by using metal sheets of lower thickness to form the plates.
Preferably, the plate comprises a first and a second large side and a first and a second small side. According to an example embodiment, the wall is arranged on at least a portion of the first large side. Advantageously, the wall extends over the entire length of the first large side.
In a complementary embodiment of the invention, the wall is also arranged on at least a portion of the first and/or second small side(s).
Advantageously, the plate has a plane of symmetry perpendicular to the large sides.
Preferably, the chased sheet metal has a thickness below or equal to 0.35 mm.
This invention also covers a tube for a heat exchanger, comprised of at least one first plate as described above. Alternatively, the tube for a heat exchanger is comprised of a first and a second plate, as described above.
According to a particularly advantageous embodiment of this alternative, the first and the second plates are arranged so that the first large side of the first plate cooperates with the second large side of the second plate.
Finally, this invention also relates to a heat exchanger including at least one flat tube, as described above.
Other features and advantages of the invention will become clear on reading the following description, provided solely as non-limiting examples of embodiments. In this description, reference is made to the appended drawings, in which:
a is a detailed view of the tube junction area according to this invention,
The appended drawings can serve not only to complement the invention, but also contribute to the definition thereof, as the case may be.
The plate 4 also comprises a central rib 14 on the surface of its internal wall, which forms a projection in the fluid flow passage 6. The rib 14 of the first plate 4 forming the flat tube 2 is held in contact with the rib 14 opposite the second plate 4 forming the flat tube 2 so as to create a separation in the fluid flow passage 6 for circulation of the fluid between the fluid inlet 8 and the fluid outlet 10 thus forming a ‘U’-shaped circulation.
In addition, the plate 4 includes a plurality of projections 12 on the surface of its internal wall, which form protuberances in the fluid flow passage 6. The projections 12 of each of the plates 4 are arranged in rows that extend in the direction of the fluid flow passage. Preferably, the projections 12 of a plate 4 of each pair of plates 4 are held in contact with the ribs opposite the other plate 4.
According to an alternative embodiment, as shown in
The heat exchanger 1 extends over a height H in a direction z, a width L in a direction x and a depth P in a direction y. The directions x, y and z form a direct dihedral.
The heat exchanger 1 includes a series of flat tubes 2 arranged alternately on the width L with inserts 16 in direction x.
The flat tubes 2 extend over the height H. Over a major portion of this height, the passages 6 of the flat tubes 2 have a substantially constant thickness ‘e’ formed by the interval between two plates 4 of the same pair.
The heat exchanger 1 comprises, at the fluid inlet 8 and the fluid outlet 10, bulges 18 with a thickness greater than the thickness ‘e’ of the passages 6 of the flat tubes 2. The bulge 18 of a plate 4 forms, with the bulge 18 of a plate 4 of the same pair of plates 4, a space for fluid circulation serving as a fluid inlet collector and a fluid outlet collector.
Each inlet collector of a pair of plates 4 is in contact with the inlet collector of an adjacent pair of plates 4 in direction x. Similarly, each outlet collector of a pair of plates 4 is in contact with the outlet collector of an adjacent pair of plates 4 in direction x. Such an arrangement enables the circulation to be achieved in position in the heat exchanger 1.
The stack of flat tubes 2 creates an interval between two pairs of adjacent plates 4 in direction x. Each of these intervals is equipped with an insert 16 formed by a thin undulated heat-conducting sheet, of which the peaks are alternately in contact with the two plates 4 of the flat tubes 2 defining the interval. In a known manner, an air flow 50, shown in
A heat exchanger bundle 1 is formed by the stack of flat tubes 2 alternating with the inserts 16. The bundle is terminated, in direction x, by two end plates 20.
The assembly formed by the flat tubes 2, the inserts 16 and the end plates 20 is secured so as to form a unitary element forming the heat exchanger bundle 1. The securing of the assembly is achieved, for example, by brazing.
The connection of the heat exchanger 1 to a fluid circuit with which it is integrated is performed by pipes 24, generally made of aluminum, leading respectively into the inlet collector and the outlet collector of the heat exchanger 1. The pipes 24 are kept secured to the heat exchanger bundle 1, in particular by brazing. The pipes 24 are connected to the fluid circuit by connection members 22.
Reference will now be made to
All of the flat tubes 2 are identical and are formed by two plates 4 made of sheets chased in the form of basins. The sheet forming the plate 4 has a thickness ‘th’. It is particularly advantageous for the thickness ‘th’ of the sheet forming the plate 4 to be below or equal to 0.35 mm. Each plate 4 is formed by two large sides 26 extending over a height H in direction z connected by two small sides 28 extending over a depth P in direction y.
Each plate 4 comprises a peripheral edge 30 forming a contour of the plate 4 extending at the level of the large sides 26 in direction y and at the level of the small sides 28 in direction z. The peripheral edge 30 is contained in a plane P.
The plane P is generally parallel to the plane containing the internal wall of the plate 4 and is separated from this plane by a distance substantially equal to half the thickness ‘e’ of the passages 6 of the flat tubes 2. The plane P contains the peripheral edge 30 of the plate 4.
When a first and a second plate 4 are assembled to form a flat tube 2, the plane P of the first plate 4 coincides with the plane P of the second plate 4.
Each plate 4 of the same pair of plates 4 is joined together in a sealed manner over the entire contour at their respective peripheral edges 30 in order to define the passage 6 for flow of a fluid.
The plate 2 also comprises a wall 40 extending from the peripheral edge 30. The wall 40 is not contained in the plane P. Preferably, the wall 40 is perpendicular to the plane P and extends in direction x opposite the internal wall of the plate 4.
The wall 40 extends in direction x by a height ‘f’. The height ‘f’ is above or equal to the thickness ‘th’ of the sheet of the plate 4.
The wall 40 extends on one of the large sides 26 over at least a portion of the height H of the plate 4. In a complementary and particularly advantageous manner, the wall 40 extends on the small sides 28 over a portion of the depth P of the plate 4.
Preferably, the wall 40 extends over the height H of the plate 4. Similarly, it extends particularly advantageously over half the depth P of the plate 4.
According to the example embodiment described, the wall 40 is continuous along the peripheral edge 30 of the plate 4. However, according to an alternative not shown, it is possible to envisage the wall 40 being separated into three segments arranged respectively on one of the large sides 26 and the two small sides 28.
Finally, according to another embodiment, the wall 40 extends only on one of the large sides 26 of the plate 4.
In the example described, each of the two plates 4 forming the flat tube 4 includes a wall 40. Nevertheless, it is possible to envisage a single one of the plates 4 including a wall 40 extending over all or some of the contour of the peripheral edge 30 of the latter.
The flat tubes 2 are formed by assembling two plates 4 together. The plates 4 are joined over their contour at their respective peripheral edges 30 so as to form a connection area 42. This connection area extends over the entire external contour of the flat tube 2.
The connection area 42 ensures the tight seal of the flat tubes 2, and, more specifically, of the fluid passages 6 with respect to the outside. In particular, the connection area 42 forms an interface impervious to the airflow 50 for the fluid circulating in the flat tubes 2.
As shown in
The airflow 50 is filled with particles, in particular water or metal, such as copper. The wall 40 prevents any direct contact between the connection area 42 and the airflow 50. The risks associated with particles from the airflow 50, in particular corrosion, are reduced. The risks of corrosion, and therefore the risks of leakage of the flat tubes, are thus reduced.
In addition, the wall 40 also enables the rigidity of the plate 4 to be improved. Thus, the wall 40 forms a rigidification rib of the plate 4. This is particularly advantageous in terms of reducing the thickness of the plate 4. The wall 40 therefore enables, once assembled with another plate 40, a particularly rigid tube 2 to be defined. This property has an impact on the mechanical performance of the heat exchanger bundle 1 and contributes to the mechanical resistance of the latter.
According to this invention, the tightness of the flat tube assembly 4 is guaranteed.
According to a second embodiment of this invention, as shown in
The plate 4 of the second embodiment has a structure identical to the plate 4 of the first embodiment. It differs therefrom by the presence of two series of openings 110, 1120, 160 and 180, arranged at the two ends of the plate 4.
Thus, the plate 4 of
According to this second embodiment, the plate 4 is such that the flat tube 2 is formed by two identical plates 4 arranged head-to-tail. In fact, the channel 220 of a first plate 4 forming the flat tube 2 is opposite the channel 240 of the second plate 4 forming the flat tube 2, and vice versa. The tightness between the two fluid passages thus created in the tube is achieved by the contact between the respective ribs 140 of the plates 4 forming the flat tube 2.
This second embodiment has the additional advantage of enabling a single model of plates 4 to be produced, which plates will be used to produce flat tubes 2 and heat exchangers 1. It therefore has an important benefit from the perspective of standardization and production rates.
This therefore enables the production costs to be reduced by mass production of the same plate 4.
Finally,
Opposite each notch 210, lugs 200 are located face-to-face with the notches 210, symmetrically with respect to a plane passing through the rib 140 and perpendicular to the general plane of the plate 4.
When two plates 4 are assembled to form a tube 2, the notches 210 of a first plate 4 cooperate with the lugs 200 of the second plate 4, and vice versa so as to facilitate the assembly and cohesion of the plates 4 with one another.
The lugs 200 serve as swaging projections and enable the peripheral contour of the flat tube 4 to be closed.
The first preferred example embodiment was described in terms of plates forming tubes having a ‘U’-shaped fluid circulation. The second example embodiment covers plates for a flat tube forming an ‘I’-shaped circulation.
According to possible alternative embodiments of the examples described above, it is possible to place an insert between the plates forming the flat tubes. These inserts are arranged in the fluid passages. This is particularly suitable for tubes made from plates according to the second embodiment shown in
This invention is very specifically applicable when a heat exchanger must be produced, for example for a heating, ventilation and/or air conditioning system intended for motor vehicles. In particular, this invention is particularly suitable for heat exchangers of the heater or cooling type, evaporators, condensers or gas coolers integrated in a heating, ventilation and/or air conditioning system of a motor vehicle.
Of course, the invention is not limited to the embodiments described above and provided solely as examples, and encompasses other alternatives that a person skilled in the art might envisage in view of the claims and in particular any combination of the various embodiments described above.
| Number | Date | Country | Kind |
|---|---|---|---|
| FR 08/01633 | Mar 2008 | FR | national |
